It wouldn't hurt to get a second opinion. Seems to me that things should have improved a little bit - at the very least. I would tell the new vet everything you've done and everything the other vet said, and tell him you're looking for a second opinion since nothing seems to be working. You never know, he might have come across this before and have more experience with it and be able to help a little more.

Poor Micah - I sure hope you find something that can help the little sweety.